1. Field of the Invention
This invention relates generally to fluid-flow-control valves and, more particularly, to a diverter-valve apparatus for use in high-pressure fluid systems having more than one operating fluid device, so as to continuously provide equalized pressure within the overall system when closed or momentarily blocked.
2. Description of the Prior Art
As is well known in the art, various problems and difficulties are encountered in providing a suitable means for controlling high-pressure surges within a fluid-pressure system.
That is, there are many types of control valves used in fluid systems, including two-way valves which provide on-and-off control of fluid devices; three-way valves which provide the option of operating either of two fluid devices, but not both devices simultaneously; and four-way valves which provide for operation of a fluid device such as a hydraulic cylinder in either of two directions, while also directing the return fluid flow through the valve to the system reservoir.
In each of these types of valves, the valve has a neutral or null position through which it must pass wherein fluid flow from the pressure source is at least momentarily blocked. In a system using a positive displacement pump, the action of such valves results in an extremely high momentary pressure surge which can damage pump parts, fittings, lines, etc. Sophisticated hydraulic systems include pressure regulators, or self-regulating variable flow pumps and accumulators to accommodate these conditions. However, a simple system, such as is used for water blasting, has a fixed positive displacement pump protected only by a pressure-relief valve. A pressure-relief valve is designed only to accommodate low rates of fluid flow, and cannot respond rapidly enough to prevent overpressuring of a high-flow system under condition of momentary flow blockage.
Flow dividers also exist which accept a given inlet fluid flow and divide this flow equally or at a predetermined ratio between two fluid devices. These characteristics are predetermined by the design of the flow divider, and do not allow for shutting off fluid flow to one fluid device independently of the other fluid device.
Several known fluid-control valves are disclosed in the following United States patents.
U.S. Pat. No. 1,240,586 is a typical cock valve having a tapered plug to regulate the fluid flow through a single inlet passage to dual outlet passages.
U.S. Pat. No. 1,807,085 discloses a two-way-valve device, whereby fluid from a single conductor may be delivered to either or both of a pair of diverging distributors.
A fluid-flow-control fixture is disclosed in U.S. Pat. No. 1,807,900 that is especially designed for use in connection with wash bowls, sinks, laundry trays, etc.
A selector valve is also disclosed in U.S. Pat. No. 3,536,101 which is particularly adapted for marine and industrial applications, wherebgy the valve must often have to withstand not only high-pressure surges, but abrasion and clogging from semi-solid materials entering along with the fluid.
However, what is needed is a diverter valve that allows one fluid device to be shut off, without affecting the fluid flow directed to another fluid device or affecting the pressure within the complete fluid system.